PRODUCTION OF SPECIFIC ANTIBODIES AGAINST GABA-TRANSPORTER SUBTYPES (GAT1, GAT2, GAT3) AND THEIR APPLICATION TO IMMUNOCYTOCHEMISTRY

Polyclonal subtype-specific antibodies were developed against three su btypes of GABA transporters (GAT1, GAT2 and GAT3). By immunoblot analy sis, each antibody detected a single band that could be blocked by abs orption of the antibody with the respective antigen. GAT2 was found in various tissues, while GAT1 and GAT3 were detected only in the brain. GAT1 was distributed throughout the brain with the highest amount in the olfactory bulb, CA3 region of the hippocampus, layer I of the cere bral cortex, piriform cortex, superior colliculus, interpeduncular nuc leus and nucleus spinal tract of the trigeminal nerve, while the GAT3 was densely found in the olfactory bulb, thalamus, hypothalamus, pens and medulla, globus pallidus, central gray, substantia nigra, deep cer ebellar nuclei and nucleus spinal tract of the trigeminal nerve but no t in the hippocampus, cerebral cortex, caudate-putamen and cerebellar dorter. GAT2 immunoreactivity was faint throughout the brain but was c oncentrated in the arachnoid and ependymal cells. Both GAT1 and GAT3 w ere found in the neuropil but not in the cell bodies nor in the white matter. These results suggest that GAT1, GAT2 and GAT3 are expressed i n different cells and that GAT1 and GAT3 are involved in distinct GABA ergic transmission while GAT2 may be related to non-neuronal function.